This isn't a technical problem. Nobody really uses iMessage enough in the EU, but in the USA where people seem to shun use of third-party messaging apps like WhatsApp, the solution would be to deem Apple a "gatekeeper" under legislation equivalent to the Digital Markets Act and force interoperability via regulation given Apple's market dominance. The regulatory process has worked with side-loading, and EU citizens wi…
Almost 80 million users of whatsapp in the US (330m pop) vs 120 million users in all of Europe (746m pop) kind of undermines that line of reasoning? If anything, the US uses whatsapp way more than Europe. If we were looking at true third party messaging platforms that aren't owned by trillion dollar mega corps that can push their products onto every phone, then... maybe? The US barely uses Telegram compared to Europe…
I might be living in a massive bubble, but WhatsApp is the canonical successor of SMS in Europe, while the few WhatsApp users that I've met in the US almost all use it to stay in touch with friends or family abroad.